Gas turbine engines, such as those that power modern commercial and military aircraft, typically include a compressor to pressurize inflowing air, a combustor to burn a fuel in the presence of the pressurized air, and a turbine to extract energy from the resulting combustion gases.
The primary air flow in a gas turbine engine is through the compressor, combustor, and turbine. A cooler, secondary air flow, may be contained more external to the gas turbine engine and/or flowing through one or more shafter internal to the engine and/or one or more bearing compartments within the engine. In some cases, this secondary air flow may leak into the primary air flow. However, leakage between the secondary air flow and the primary air flow may be prevented or reduced by the use of one or more brush seals. In many turbine engines, this cooler, secondary air flow, may be contained in air compartments at a higher pressure than the air flowing through the compressor, combustor, or turbine.
Conventional systems have therefore utilized one or more brush seals having bristles, to limit uncontrolled secondary air flow into the compressor, combustor, and/or turbine. Conventional seals are often placed between rotating parts of a turbine, such as between rotating blade disks and stationary vane flanges. These seal systems have typically relied upon the rotation of one surface relative to another surface to force the bristles of a brush seal into sealing contact. For example, these systems have typically relied upon the pressure generated by a turbine stage set forward of an aft turbine stage to urge the brush seal bristles into sealing contact.